1. Field of the Invention
The present invention relates to a toner conveyer device that conveys waste toner.
2. Description of the Related Art
In conventional image forming apparatuses such as copiers, facsimile machines, and printers, a service staff generally carries out replacement of consumable or life-limited components and maintenance of them. However, the trend is changing and the user is carrying out exchange of supplies and maintenance. In addition, smaller components are used for suppressing the size and the cost of the image forming apparatus. Therefore, the user needs to periodically exchange parts that deteriorate in quality earlier than the life of the apparatus or a waste-toner container. The waste-toner container contains residual materials such as toner, which is a developer, or fiber from transfer sheets. Moreover, because the image forming apparatus is installed adjacent to a user of a personal computer in the times of widespread use of personal computers reduction of noise during operation of the image forming apparatus is another problem that needs attention.
Toner that fails to be transferred onto the transfer sheet is removed and conveyed into a waste-toner container. To recycle the waste toner, an additional path and an additional driving unit for collecting the waste toner becomes necessary. As a result, the image forming apparatus becomes larger. The waste toner contains foreign materials such as fiber from the transfer sheets. Removal of the fiber makes control process or reuse process complicated. If a full-color image forming apparatus that uses three or four toners performs the waste-toner recycling process, considerably larger waste-toner container is required so that structure of the full-color image forming apparatus becomes much complicated. For this reason, in some of the image forming apparatuses, the waste toner is just conveyed into the waste-toner container and the waste-toner container is replaced with another one when the waste-toner container is full with the waste toner.
It is possible to provide a waste-toner container that can contain all the waste toner generated during a whole life of the apparatus. However, such a waste-toner container is considerably large. Therefore, there is a need for filling the waste toner into the waste-toner container in an effective manner to decrease the frequency of replacing the waste-toner container. The waste toner is poured into the waste-toner container from the top, and a sensor is installed on the top part of the waste-toner container. The sensor is a detecting unit for detecting whether the waste-toner container is filled to its capacity and for notifying time of exchange. Exchange cycle of the waste-toner container is prolonged if the waste-toner container is filled with the waste toner without an unfilled space, that is, the waste toner does not accumulate in one particular part of the waste-toner container.
In the conventional image forming apparatus two methods are used to properly fill up the waste-toner container. One method is to periodically shake the waste-toner container and the other method is to locate an agitating screw on the top part of the waste-toner container to flatten a pile of the waste toner inside the waste-toner container.
Japanese Patent Application Laid-open No. H11-327397 discloses an image forming apparatus that includes an photoconductor, a cleaning device that cleans a toner-image formation surface of the photoconductor, a cleaner case (waste-toner conveyer path) that conveys the waste toners removed by the cleaning device, and a toner conveyer screw (screw member) that conveys the waste toners. The image forming apparatus further includes a hammer member (impact-pressure making unit) that gives an impact to the cleaner case or the toner conveyer screw. The hammer member gives an impact when the image formation process is not performed by the photoconductor. More particularly, in the cleaner case there is an elastic projection arranged in contact with a thread of the toner conveyer screw. When the toner conveyer screw is rotated, the projection is brought into contact with the thread in an electrical manner to give vibration to the toner conveyer screw. Then, the toner adhered to the toner conveyer screw falls due to the vibration, thus preventing decrease of a conveyable waste-toner amount.
Japanese Patent Application Laid-open No. 2002-241569 discloses a residual-toner recovery device for use in an image forming apparatus that includes a residual-toner dropping path through which the residual toners fall down and a conveyer path that connects between the residual-toner dropping path and the residual-toner recovery container. The toner adhered to a peripheral surface of a toner-image forming unit are removed from the toner-image forming unit by a cleaning mechanism and fall down through the residual-toner dropping path. A residual-toner conveyer mechanism includes a sweep roller having an elliptical cross section, positioned near the connection with the conveyer path in the residual-toner dropping path, and a scraper made of a flexible member, having the distal end pressed against the peripheral surface of the sweep roller in the return side of the rotation direction, with the proximal end of the scraper fitted to the inner wall of the residual-toner dropping path. The scraper is formed with a recess at parts other than the part which is in contact with the sweep roller. With this arrangement, the increase of the internal pressure of the residual-toner dropping path on which the return side of the sweep roller in the rotation direction is positioned can be suppressed, while maintaining the toner-scrape performance of scraping the toners adhered to the sweep roller positioned in the residual-toner dropping path.
However, in the conventional image forming apparatus, collected waste toner accumulates unevenly in the waste-toner container, and space in the waste-toner container is not effectively filled.
Moreover, electrophotographic devices have become smaller so that a range of users has become broader. However, a shorter conveyance path makes it difficult to maintain efficiency in conveying waste toner. There is a need for improving the efficiency.